Here is a list of the various groups, who qualifies for them and the call sign format: The format refers to the number of prefix and suffix letters before and after the area numeral. For example: a Group "A" 1x2 format indicates the call sign has one prefix letter - followed by ("x") the area numeral - and two suffix letters. Amateur Extra Class amateurs qualify for Group A call signs.

For Amateurs in the lower 48 Continental (contiguous) United States

Group A -- Amateur Extra Class
Contains all K, N and W 1x2, most 2x1 and most "AA-AK" prefixed 2x2 call signs

Group B -- Advanced Class
Contains most K, N, and W prefixed 2x2 call signs

Group C -- Technician, Tech Plus. & General Class
Contains all N 1x3 call signs. Unassigned W and K prefixed 1x3 call signs are not issued under the sequential call sign system but are available under the Vanity call sign system

Group D -- Novice Class
Contains most K and W prefixed 2x3 call signs. The letter X may not be the first digit of the suffix. No provision has been made for the issuance of AA-AL and NA-NZ prefixed 2x3 call signs and these call signs are not issued to anyone.

For Amateurs located outside of the 48 Continental United States

Group A -- Amateur Extra Class
AH. KH, NH, and WH prefixed 2x1 call signs are issued to amateurs in the Pacific Area. AL7, KL7, NL7 and WL7 2x1 call signs are reserved for Alaska and KP, NP, WP 2x1 call signs are reserved for the Atlantic Area)

Group B -- Advanced Class
AH. KH, NH, and WH prefixed 2x2 call signs are issued to amateurs in the Pacific Area. AL7 2x2 call signs are reserved for Alaska and KP 2x2 call signs are reserved for the Atlantic Area.

Group C -- Technician, Tech Plus & General
KH. NH, WH 2x2 prefixed call signs are issued to amateurs in the Pacific Area. KL7, NL7 and WL7 2x2 call signs are reserved for Alaska and NP and WP 2x2 call signs are reserved for the Atlantic Area.

Group D -- Novice
KH and WH prefixed 2x3 call signs are issued to amateurs in the Pacific Area. KL7 and WL7 2x3 call signsare reserved for Alaska and KP and WP 2x3 call signs are reserved for the Atlantic Area.